The senior members of the British royal family reunited on Friday evening as they headed to Cornwall for the G7 summit, during which Kate Middleton accidentally revealed her surprising personal nickname for her father-in-law, Prince Charles.

The moment that Prince Charles and his wife Duchess Camilla turned around to see William and Kate joining them was caught on camera, and a lip reader is confident that the Duchess of Cambridge greeted Prince Charles by calling him "Grandpa," seemingly out of habit due to what she taught her three children to call him.

A lipreader that spoke to Cornwall Live claimed that the Duchess was saying to the heir apparent: "Hello Grandpa! How are you?" Charles spoke to her for a few seconds with his back to the camera before turning around to greet Prime Minister Boris Johnson and his wife Carrie who were talking to Queen Elizabeth II.

There were a few other adorable moments shared between the family members at the royal engagement. The lip-reader revealed that the shawl Camilla is seen holding in the same video was for the Queen, as she reportedly asked her mother-in-law if she would like to wear the garment, to which the Queen replied: "You have it."

Another video that went viral from the day showed Kate and Camilla accompanying the Queen, their first joint royal engagement since the pandemic, as they attended an event in celebration of The Big Lunch initiative at The Eden Project.

The video captured the monarch's playful side as she insisted on cutting a cake celebrating the launch with a large ceremonial sword. When an aide pointed out that there was also a knife on the table, the 95-year-old replied: "I know there is! This is something that is more unusual."

Camilla and Kate shared smiles while the Queen approached the cake with second thoughts about her plans and said she didn't think it was "going to work." The Duchess of Cornwall stepped in to help her mother-in-law saying "Do you think two hands?", and the cut the white cake down the centre together.

The Queen proudly beamed at their work before removing the sword and passing it off to an aide.

Prince Charles
Prince Charles, Kate Middleton, and Prince William Getty